An improved cement mixer having polyethylene cement mixing drum (20) held and supported by a cradle arm assembly (21) formed of cradle base support braces (23) and upright cradle arms (22) which interfit into crandle arm recesses (27) which are preformed with polyethylene drum (20). A bull gear (25) is provided and circumvolves polyethylene drum (20). Bull gear (25) is aligned with and attached to cradle arms (22) and drum (20) so they dual function both as a drive mechanism for rotating drum (20) and as a structural member for cradle assembly (21).